Field of the Invention
The present invention relates to mobile communication.
Related Art
3rd generation partnership project (3GPP) long term evolution (LTE) evolved from a universal mobile telecommunications system (UMTS) is introduced as the 3GPP release 8. The 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in a downlink, and uses single carrier-frequency division multiple access (SC-FDMA) in an uplink. The 3GPP LTE employs multiple input multiple output (MIMO) having up to four antennas. In recent years, there is an ongoing discussion on 3GPP LTE-advanced (LTE-A) evolved from the 3GPP LTE.
As disclosed in 3GPP TS 36.211 V10.4.0 (2011-12) “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 10)”, a physical channel of LTE may be classified into a downlink channel, i.e., a PDSCH (Physical Downlink Shared Channel) and a PDCCH (Physical Downlink Control Channel), and an uplink channel, i.e., a PUSCH (Physical Uplink Shared Channel) and a PUCCH (Physical Uplink Control Channel).
Meanwhile, communication between UEs which are physically closed to each other, that is, device to device (D2D) communication) is required due to an increase in user requirements for a social network service (SNS).
The D2D communication may be called a proximity service (ProSe). In addition, a UE that performs the proximity service may be called a ProSe UE. In addition, a link between the UEs used in the D2D communication may be called a sidelink.
Meanwhile, UE should adjust or switch an RF chain of a transceiver in order to perform D2D communication. According to the above switching, cellular communication (or WAN communication) with a base station should temporarily interrupt. However, no researches and studies have been performed toward the temporary interruption up to now. Further, there is no discussion how long the temporary interruption is allowed up to now.